This proposal requests funds to purchase a Hitachi S-520 scanning electron microscope with a Kevex 8000 energy dispersive x-ray analyzer. The instrument would represent the only state-of-the-art scanning electron microscope available in area academic institutions. The microscope would serve as an important research instrument for eight users, five of whom currently have NIH support. The microscope will provide high resolution scanning electron microscopy as well as scanning transmission electron microscopy. The Kevex 8000 energy dispersive analyzer, considered one of the most technically advanced systems available, will permit reliable quantitative microanalysis of the elemental content of individual cells or antibody end products within cells or tissue. The instrument will be housed in the Department of Anatomy at the Medical College of Wisconsin. Space has already been reserved for the equipment. The operation of the equipment will be supervised by the principal investigator who has had 14 years experience in scanning electron microscopy and elemental microanalysis. The administration of the equipment will be assisted by a "Policy Committee" consisting of the principal users listed in this proposal.